Database Features
Tips and Tricks on using Exasol - from SQL and Lua Scripts to transactions and performance
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When to use which programming language in Exasol? This article helps you to find the right language for your task.
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MERGE is designed to use a small UPDATE table to affect a larger FACT table. This article explains how it works
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If you want to implement Column Level Security in addition to Row Level Security, this example shows you how this can work using Virtual Schemas
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Generally speaking, NULL is not a special value, but it represents an undefined value. This article describes how to work with NULL values and the types of valid comparisons
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NULL and nil have two different meanings in the context of Lua Programming. This article explains the difference
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Problem Working with DOUBLE values sometimes results in inaccuracy.   Diagnosis Those inaccuracies are not unexpected when dealing with DOUBLEs. As DOUBLE is an approximative data type, some values can not be stored exactly. This is a general issue of floating-point arithmetic.   You can verify the data type of your column by creating a table using the query and viewing the data types for the newly-created column, for example:  CREATE TABLE TEST AS SELECT ROUND(((71222-65504)/65504*100) ,1); -- Creates a DOUBLE   Solution You can use an exact numeric type, like DECIMAL to remove inaccuracies.  Such as the example below:   SELECT ROUND( CAST ((71222-65504)/65504*100 AS DECIMAL (16,3)) ,1); > 8.7 SELECT cast (1 as DECIMAL (17,16)) - cast (1E-16 as DECIMAL (17,16)) AS exact; > 0.9999999999999999   Additional References https://docs.exasol.com/sql_references/data_types/datatypedetails.htm#NumericDataTypes
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